Bicycle bottom bracket

ABSTRACT

A crankset is provided with a spindle rotatably disposed through a bottom bracket shell; two pedal cranks each including a bifurcation at one end and a through hole formed through one arm of the bifurcation; and two compression collars each including a lengthwise slit, two yoke arms each projecting out of the compression collar, a through aperture through one end of one yoke arm, and a threaded hole through one end of the other yoke arm. The through aperture is aligned with the threaded hole. Each compression collar is complimentarily engaged with the bifurcation. Either end of the spindle anchored in the compression collar. Either fastener is driven into either end of the spindle to fasten the compression collar and the spindle together. Either bolt is driven through the through hole and the through aperture into the threaded hole to fasten the pedal crank and the compression collar together.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to bicycle parts and more particularly to abicycle bottom bracket with improved characteristics.

2. Description of Related Art

Conventionally, a bicycle crank comprises one hole at one end forconnecting to a pedal and the other hole at the other end for connectingto an axle of bottom bracket. The other hole includes ridges and grooveson an inner surface. Either end of the axle includes ridges and grooveson an outer surface so that the axle may be co-rotated with the rotatingcrank. There are gaps between the ridges of the crank and the axle.Thus, the ridges of the crank may impact ridges of the axle when a riderstarts to rotate the crank. Disadvantageously, this not only makes noisewhen riding but also causes wear between the ridges. The larger the gapsthe sooner the crank disengages from the axle. Thus, the need forimprovement still exists.

SUMMARY OF THE INVENTION

It is therefore one object of the invention to provide a bicycle bottombracket comprising a spindle rotatably disposed through a bottom bracketshell; two pedal cranks each including a bifurcation at one end and athrough hole formed through one arm of the bifurcation; and twocompression collars each including a lengthwise slit, two opposite yokearms each projecting out of the compression collar, a through apertureformed through the open end of one yoke arm, and a threaded hole formedthrough the open end of the other yoke arm, wherein the through apertureis aligned with the threaded hole; wherein each of the compressioncollars is complimentarily engaged with the bifurcation; wherein eitherend the spindle is matingly inserted into the compression collar;wherein two fasteners each are driven into either end of the spindle tofasten the compression collar and the spindle together; and wherein twopinch bolts each are driven through the through hole and the throughaperture into the threaded hole to fasten the pedal crank and thecompression collar together.

The above and other objects, features and advantages of the inventionwill become apparent from the following detailed description taken withthe accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded view of a pedal crank and a compression collar ofa bicycle bottom bracket according to the invention;

FIG. 2 is a perspective view of the assembled pedal crank andcompression collar of FIG. 1;

FIG. 3 is a perspective view of the compression collar;

FIG. 4 is a side elevation of the compression collar shown in FIG. 3;

FIG. 5 is a sectional view taken along line 5-5 of FIG. 4;

FIG. 6 is an exploded view of the assembled pedal crank, compressioncollar, and a pedal to be mounted on a spindle which is rotatablydisposed through a bottom bracket shell of a bicycle;

FIG. 7 is a perspective view of the assembled bottom bracket shown inFIG. 6; and

FIG. 8 is a sectional view taken along line 8-8 of FIG. 7.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 1 to 8, a bottom bracket in accordance with theinvention is shown. The bottom bracket is part of drive of a bicycle 1.The bottom bracket comprises the following components as discussed indetail below.

A spindle 12 is rotatably disposed through a bottom bracket shell 11with both splined ends exposed. Two pedal cranks 2 each are an elongatedhollow member having one holed end attached to a pedal (not numbered)and the other bifurcated end 20. A through hole 21 is formed through onearm of the other bifurcated end 20.

Two compression collars 3 each are shaped as a split cylinder andcomprise a lengthwise slit 31, a through opening 32 being partiallysplined on its inner surface, and two opposite yoke arms 33 each havingone end integrally formed with the main body of the compression collar 3and the other open end projecting out of the main body of thecompression collar 3 a short distance. As shown in FIG. 4, two gaps 333are formed between top of the yoke arm 33 and the main body of thecompression collar 3 and between bottom of the yoke arm 33 and the mainbody of the compression collar 3 respectively. A through aperture 331 isformed through the open end of one yoke arm 33 and a threaded hole 332is formed through the open end of the other yoke arm 33. The throughaperture 331 is aligned with the threaded hole 332.

The compression collar 3 is sized and shaped to the other bifurcated end20 so that in assembly the compression collar 3 may be complimentarilyengaged with the other bifurcated end 20 with the through aperture 331,the threaded hole 332, and the through hole 21 being aligned. Next,insert one end of the spindle 12 into the through opening 32 of thecompression collar 3 so as to matingly engage the spindle 12 with thecompression collar 3. Next, drive two screws 5 each into internalthreads (not shown) formed in one splined end of the spindle 12 tofasten the compression collar 3 and the spindle 12 together. Finally,drive two pinch bolts 4 each through the through hole 21 and the throughaperture 331 into the threaded hole 332 to fasten the pedal crank 2 andthe compression collar 3 together.

It is envisaged by the invention that the invention has a decreasednumber of components, is easy to assemble or detach, and is durable.

While the invention has been described in terms of preferredembodiments, those skilled in the art will recognize that the inventioncan be practiced with modifications within the spirit and scope of theappended claims.

1. A crankset comprising: a spindle rotatably disposed through a bottom bracket shell; two pedal cranks each including a bifurcation at one end and a through hole formed through one arm of the bifurcation; and two compression collars each including a lengthwise slit, two opposite yoke arms each projecting out of the compression collar, a through aperture formed through one yoke arm, and a threaded hole formed through the other yoke arm, the threaded hole being aligned with the through aperture; wherein each of the compression collars is complimentarily engaged with the bifurcation of the pedal crank; wherein either end the spindle is releasably fastened in the compression collar; and wherein two threaded fasteners each are driven through the through hole of the bifurcation and the through aperture of the compression collar into the threaded hole of the compression collar to fasten the pedal crank and the compression collar together. 